In a bowl, combine flour and baking powder. Dig a well and add the eggs and softened butter. Mix well, then stir in sugar and vanilla sugar. Mix by hand until dough comes together. Refrigerate for an hour.
Preheat oven to 350°F. Press the dough into a large gratin dish covered with a parchment paper. Spread out your desired amount of jam on the dough.
For the nut topping, ground the almonds and hazelnuts. In a pan, melt the butter with the sugar and vanilla sugar. Add the ground almonds and hazelnuts, and cook a low heat, stirring constantly. Evenly distribute the mixture on the apricot jam. The surface should be smooth.
Bake for about 2 hours then let cool fully before unmoulding. Cut into rectangles then into triangles
Melt the chocolate and the cream on low heat. Dip the tips of the triangles into the chocolate and allow it to harden.